Die for pressure casting



G. W. BUNGAY DIE FOR PRESSURE CASTING Original Filed April 20, 1917 2 Sheets-Sheet l ill W J & llll-llllllll I; 1 -1 Nov. 2 24. 3,536,667

G. V l. BUNGAY DIE FOR PRESSURE CASTING Original ile pril 20, 1917 2 Sheets-$heet 2 Patented] Nov, 25, 19924 enact? Friar ames;

GEORGE WALDEMAR BUNGAY, BROOKLYN, NEW YORK, ASSIGNOR, BY MESINE A53 SIGNMEN'TS, T0 ALUMINUM DIE-CASTING CORPORATION, OF GAB-WOOD, NEW JER- SEY, A CORPORATION OF NEW JERSEY.

1on1 non rnnssunn oas'rme.

Griginal application filed April 20, 1917, Serial No. 163,405. Divided and this application filed May 23,

accompanying drawings, forming part thereof.

My invention relates to pressure casting or die casting and relates more particularly to means for the forming of tubular bodies, such, for example, as the usual tone arms of phonographs, and is a division of the subject matter originally included in my application for patent Serial No. 163,405 filed April 20, 1917. The usual meansheretofore of casting these tone arms has been to have the gate through which the molten metal is supplied to the mold or die at a, middle point ofthe tone arm and when the tone arm is of the usual curved or elbowshap je, this gate iscommonlyplacedjn the die or mold so as to be located at the outer side'of the bend. or elbow, and there is left on the/casting at this point when the sprue is ,removed an unsightly spot which, alter the casting is .finished, is porous and which also may contain blow'holes in the adjacent body of the tone arm, so that in plating the casting the porousmetal at this point absorbs most of the plating metal, leaving the spot rough and in an unsightly condition. I have dlscovered that by providing means for gating the casting at one or both ends and by providing feeding chambers or distributing chambers in the die or mold from which-the molten metal flows through narrow and preferably annular gates, into the end or ends of the interior mold space for forming the tubular body or tone arm, the above noted diiiiculty is overcome, by reason of the fact that the casting for the tone arm when removed from the mold or die will have formed thereon, at one or both ends thereof a projecting boss which, when a core is employed at that end, will be of annular form, and this boss will be united to the adjacent end of the tone arm by a thin neck corresponding tothe narrow annular gate 1917. Serial No. 170,388. 7.

and this boss, having the sprue thereon, can be, sawed oil or severed from the body of the tone arm, and this detached or severed boss will be found to contain anyporous metal and the body of the castingor tone arm can be finished and plated without having therein blow holes and such finished casting will' not have thereon any rough or unsightly spots.

I shall now describe the die or moldot my invention with reference tothe accompanying drawings, illustrating several embodiments thereof, and shall thereafter point out my invention in claims.

Figure 1 is a vertical section on a plane indicated by the line 1-1 of Figure 2 as viewed from the left, and is an inner face view of one ,of the die members together with the cores appearing in elevation.

Figure 1 is an enlarged partial transverse horizontal section on. a plane indicated by the line 11 of Figures 1 and 1 as viewed from above and, illustrates the narrow annular gate or inlet for the molten metal opening from the feeding chamber into the cylindrical end of the mold cavity.

Figure lis a further enlarged partial section on the plane of Figure l and on a plane indicated by the line 11 of Figure 1 as viewed from below.

Figure 2 is a vertical transverse section on slightly oil'set planes indicated by the line 2-2 of Figure 1 as viewed from the right.

Figure 3 is a side elevation, partly in central vertical section, of the unfinished casting for a phonograph .tone arm after this casting has been removed from the mold or die illustrated in Figures land 2.

Figure 4 is a side elevation of the casting appearing in Figure 3 after it has been finished.

Figure 5 is a view similar to Figure 1 illustrating a modification in which the casting is gated at one end only.

Figure 6 is a similar. view illustrating a further modification in which the casting is gated centrally at one end thereof.

The mold or die illustrated in Figures the contiguous faces thereof for forming a mold cavity 3 of bent or elbow shapeand into which, cores 4 and 5 extend from oppo site ends, between the members 1 and 2, in a direction parallel with the meetingsurfaces of these members and occupying equal spaces in each of the recesses forming the mold cavity 3. These cores are held in place by means of. usual guide sleeves 6 and 7 carried" by one of the die members in the usual way. At the opposite, ends of the mold cavity 3, in the construction shown in the drawings, similar narrow annular ates 8 are providedbetween slight external shoulders 9 on the core members 4 and 5 and similar internal shoulders 10 (Figures 1 and 1") formed by the die members 1 and 2. The cores 4 and 5 have reduced inner portions 11 and 12 inward from the shoulders 9, and the rounded beveled endsof these inner portions meet or come-together at the turn orbend in the body cavity 3, as appears in Figure 1. The narrow annular gates 8 form inlets into the opposite ends of the main chamber or cavity 3 from enlarged end parts of the mold cavity which form similar annular feeding chambersor distributing chambers 13, shown as formed by rounded annular grooves in the die members 1 and 2.

The two "feeding chambers or distributing:

chambers 13 are adapted to have molten metalforced into them substantially simultaneously through supply ducts or runners 14 and 15 which join to form a main supply duct or trunk 16. ,These supply ducts 14, 15 and 16 are-formed by grooves in the face of one or both of the die members 1 and 2, and in the construction illustrated in the drawings such duct-forming grooves are shown /as provided in both of the die members 1 and 2, as will be clear from. .Figure 2. The main supply duct or trunk 16 leads from or communicates with a recess 17 shown as formed in the edges of the die members 1 and 2, this recess 17 being for the reception of the nozzle of a die-castin machine for forcing the molten. metal un er pressure through the ducts or runners 16, 14 and 15 into'the distributing chambers or feeding chambers 13, from' which it is forced through the narrow annular gates 8 concurrently into the op posite ends of the main chamber 3 'of the die or mold The feeding chambers 13 have sufficient capacity to distribute the molten metal completely around their circular course, and, in the construction shown. in the drawin s, this metal is forced from the feeding chambers 13 all of the way' around or throughout the extent of the annular gates 8 intothe cylindrical ends of the maincasting cavity or space 3 so that this space will be quickly and evenly' filled with the inflowing molten metal, the

flow of which is distributed around the complete circle of the cylindrical ends thereof. a

The rough casting 18 (Figure 3) as it comes from the mold or die ,will have formed thereon thickened rounded enlarged parts forming end bosses 19, corresponding tothe location of the feedin chambers or distributing chambers 13 in t e die or mold and which will be connected to the body of the. casting 18 by means of thin annular necks 20, corresponding to the narrow annular gates 8'. From the end bosses 19 a branchlng sprue 21' is shown as extending and corresponding tothe inlet ducts 14, 15 and 16in the die or mold. It will be noted as of importance that this sprue 21 does not connect directly to the body of the casting 18 but only to the sur-- faces Where the necks 20 were sawed,

through than it would be, or has heretofore been in the prior art, to finish a casting from which a sprue has been detached froin its curved surface in a conspicuous place, and which commonly has been at a middle ,point thereof upon its outward rounded surface, and where, as hereinbefore In finishing the casting s. the

When

inc.

mentioned, a rough place is thereby left into which most of the plating metalsisabsorbed, so that a. good finish cannot be obtained at this point; which is left in an unsightly condition, and this serious trouble has been entirely done awayrwith by my present invention.

f The casting 22 shown-win Figure4. is a phonograph tone arm of the bent or el bow shape there appearing, and at its ends is of cylindrical cross-section, as is indicated in the drawings, particularly in Figures 1 and 2 thereof. Such tone arms of any desired 7 length accordingto theparticular phonograph upon which they are designed to "be used,and --in some instances of considerably greater length than the illustrated tone I arm 22, may be successfully castby means of my invention. The annular gates Sand feed ing chambers or distributing chambers 13 provide for the successful casting of these ong tone arms, by-supply'ing the molten metal under pressure at both ends thereof around which it isfdistributed and from which it flows and is united'at the middle of the central chamber 3 of the die or mold,

i invention is illustrated in Figure 5 of the drawings. In the mold or die construction there illustrated as an embodiment: of my invention, a 'die member 23, is shown as pro-\ vided, and which is co-operative with a substantially complementary die member not shown and which forms therewith a main casting-receiving die cavity 24 into which projects from opposite ends thereof meeting cores 25 and 26 shown as arranged at right angles to each other, similar in this respect to the cores 4: and 5 illustrated in Figure 1 and also for similarly forming a casting of an elbow shape corresponding to the mold cavity 24 illustrated in Figure 5. As is shown in the drawings, the upper or vertically arranged core 26 closes the mold cavity 24 at the upper end thereof, no gate being provided at this point. At the other or lower and left end of the mold cavity 24, however, a narrow annular gate 27 is provided at the end of the cavity 24: surrounding thecore 25, this gate 27 being shown as formed between an external shoulder 28 on the core 25 and a corresponding oppositely arranged internal shoulder shown as formed in the die member 23. An annular feeding chamber or distributing chamber 29, of sufiicient capacity is shown as provided. A runner or inlet duct 30 communicates with a recess 31 in the edge of the mold and opens into the feeding chamber 29, and this runner or duct 30 may be formed only in the die member 23, as appears in Figure 5, or it may be formed by co-operating grooves in both of the die members. The operation and' results of the construction illustrated in Figure 5 are substantially the sameas have been hereinbefore explained in reference to Figures 1 to 4 inclusive.

In cases where the tone arm or other similar tubular casting is straight, so as not to require the inserting of a core from each end, the gating. of the casting may take place centrally of the end oppositeto which the. core'is inserted, and the carrying out of my invention in this way is illustrated in Figure 6, with a die member 32 which is co-operative with a complimentary die member, not shown. There is provided a single-core 33 together with which the die members form A narrow "annular gate 35 opens into the lower end of the-mold cavity '34 and is formed in the mold members around the lower end of the core 33- and provides an inlet or gate into the mold'cavity 34 from a centrally arranged upwardly and outwardly extending feeding chamber or distributing chamber 36, into the center of which at the lowest. point thereof there opens a supply duct or runner 37 which communicates with or leads fromfa nozzlereceiving recess 38 in the end of the die.

Bv referringto Figure 6, it will be evident that the casting produced in the die or mold there illustrated will, as it comes from the mold in rough form, have at one end thereof a cap-shaped boss corresponding to the feeding chamber 36 and this boss willhave a sprue projecting therefrom corresponding to the duct 37, and this boss will be united to the end of the casting by a thin annular neck corresponding to the gate or inlet 35, and in finishing the casting this end boss is severed or sawed off from the casting through such thin neck at the end thereof, as will be readily understood, and whereby the outer curved surfaces of the finished casting will be in perfect condition without the heretofore usual rough place or imperfection due to the detachment therefrom of a sprue.

It is obvious that various modifications may be made in the' constructions shown in the drawings and above particularly de scribed within the principle and scope of my invention.

I claim:

1. A die for pressure-casting having a tubular mold cavity and a flow conduit leading into the annular end thereof through a gate-stricture formed to mold a reduced sprue section on the annular end of a tubular casting.

2. A die for pressure-casting having a tubular mold cavity and a flow conduit lead- 7 ing into the annular end thereof through an annular gate-stricture formed to mold a reduced annular sprue section projecting from the annular end of a tubular casting.

3. A die for pressure-casting having a tubular mold cavity and a flow conduit leading into the annular end thereof through an 7 annular gate-stricture formed to mold a reduced. annular, sprue projecting from the annular end of a tubular casting with a demarcating shoulder at the juncture of the casting and sprue.

4. A die for pressure-casting comprising a core and separable complementary parts recessed to form a tubular mold cavity around said core and a gate-stricture around said core leading into the end of said tubular mold cavity and a flow conduit leading into said gate-stricture. the main casting-receiving mold cavity .34.

5. A die for pressure castings comprising complementary die sections having formed therebetween a mold cavity provided with a flow conduit communicating therewith, a core disposed within said cavity, said core being spaced from the wall of said mold cavity and formingat its jointure with said conduit a gate stricture of less cross sectional area than said cavity and conduit respectively.

6. A die for pressure-castings comprising complementary die sections having formed therebetween a mold cavity provided with a flow conduit communicating therewith, a core disposed within said mold cavity, said rcore being spaced from the wall of said conduitbut-forming therewith a gate stricture intermediate said cavity and conduit of less cross sectional .area than said cavity and flow conduit respectively.

,7. A die for pressure castings comprising.

complementary die sections having formed therebetween a mold cavity provided with a flow conduit communicating therewith and of a less cross sectional area than the cavity,

a core disposed within said mold cavity, said core being so positioned with respect to said flow conduit and mold cavity as to form therebetween-a gate tricture adapted to accommodate an integral section formed at the end of the casting, the surface of said section at its jointure with the casting being receded with respect to the surface of the casting.

' 8. A die for pressure castings comprising complementary die sections recessed to form a mold cavity having a flow conduit communicating concentrically therewith and .of a less cross sectional area than the cavity, a

core disposed within said cavity, said core bein so positioned with respect to said flow conduit and cavity'as to form .therebe- 'formed therein and aflow conduitof less diameter leadin into the cavity, acore disposed within said cavity, said core being so spaced from the Wall of said conduit and cavity as to provide therebetween an annular gate stricture of less cross sectional area than said cavity and conduit respectively,

said stricture being adapted to accommodate an integral section formed at the end of the casting withv a demarking shoulderat its jointure therewith the depth of which corresponds to the difference between the diameter-of the conduit and cavity respectively.

In testimony whereof I have alfix'ed my signature.

GEORGE WALDEMAR BUNGAY. 

